Electrically controlled clutch



Aug- 4, 1959 N. l.. BROATCH ELECTRICALLY CONTROLLED CLUTCH 3Sheets-Sheet 1 Filed Aug. 2, 1956 INI/EN TOR /Vasa/v Ra/)raw LUL@ Aug.4, 1959 N. L. BRoA-rcH 2,397,679

ELECTRICALLY CONTROLLED CLUTCH Filed A'ug. 2, 195e :s sheets-sheet 2Aug. 4, 1959 N. L. BRoATcH ELECTRICALLY CONTROLLED CLUTCH 3 Sheets-Sheet3 Filed Aug. 2. 1956 INVENTOR. Wada/v EE0/1 raw GAC?.

ELECTRICALLY CONTRLLED CLUTCH Nelson L. Broatch, Torrance, Calif.,assignor to the United States of America as represented by the Secretaryof the Air Force Application August 2, 1956, Serial No. 601,847

2 Claims. (Cl. 74-125.5)

This invention relates to a driving mechanism wherein a continuouslyturning shaft acts as means for rotating a shaft which is normally heldstationary. More particularly, the invention provides means foroperating a camera or other device from a continuously rotating shaft byincluding clutch means for engaging and disengaging the driven shaftfrom said continuously rotating shaft.

In aerial photography, exposures are made in rapid succession and anecessary requirement is the precise timing of the shutter and filmmovements with each other, That is, the film must be held perfectlystationary during the time the shutter is open and, after the shuttercloses, the film must move rapidly to bring the next succeeding frameinto its proper position with respect to the shutter and must be broughtto rest before the shutter reopens. This type of movement usuallyrequires the translation of direct rotary motion 'of a continuouslyrotating shaft through an engaging and disengaging means to a normallystationary shaft which controls the shutter and film movements.

The object of the invention is to provide a positive and relativelysimple means having a minimum of moving parts for permitting rotation ofa normally stationary shaft from a continuously rotating shaft.

Another object of the invention is the provision of a mechanism forautomatically controlling film movement and shutter position by rotatinga normally stationary shaft through operator controlled means by acontinuously driven shaft.

A further object of the invention is to provide a means for positivelystarting and stopping the rotation of a normally stationary shaft atpredetermined locations of its cycle.

A still further object of the invention is to provide a combination ofsolenoid and cam means for alternately engaging and disengaging a pawlmember from a constantly turning toothed disc.

These and other advantages, features and objects of the invention willbecome more apparent from the following description taken in connectionwith the illustrative embodiments in the accompanying drawings wherein:

Fig. l is a pictorial isometric drawing showing the assembled mechanismwith the pawl and ratchet in the engaged position so that theintermittently rotatable shaft rotates simultaneously with thecontinuously rotating shaft;

Fig. 2 is a View of the pawl and ratchet mechanism shown in Fig. l inthe disengaged position and rotated 180 from the position shown in Fig.l. With the pawl and ratchet arranged as in this View, the driven shaftis in its normal stationary position;

Fig. 3 is a View in side elevation of the assembly showing the pawl andratchet in the engaged position, 90 from the at rest position as shownin Fig. 2. Also shown is the actuator in the energized position havingreleased the pawl a short time before;

Fig. 4 is the top view of assembly as shown in Fig. 3

2 with the actuator system omitted so that the details of the pawl andratchet arrangement may be seen more clearly;

Fig. 5 is a view similar to Fig. 3 in side elevation yof the assemblyshowing the pawl and ratchet in the disengaged position. Also it may benoted that the actuator is not energized and the pawl is being held outof engagement with the ratchet;

Fig. 6 is a top view of the assembly as depicted in Fig. 5 with theactuator assembly omitted for the sake of clarity; and

Fig. 7 shows an alternate spring arrangement for urging the pawl intoengagement with the ratchet after the pawl has been released from its atrest position by the action of the actuator and for holding the pawl inengagement for the duration of the cycle.

The illustrated embodiment of the invention, as shown in Fig. l, isarranged preferably to be used in conjunction with the shutter operatingand film transporting mechanism of an aerial camera wherein successiveexposures are made of the terrain over which the plane is flying. Sinceexposures are made in rapid succession, the film transport mechanism ofthe camera must be posi-tively stopped and locked in position to preventfilm movement during shutter operation. To accomplish this result, theinvention contemplates means arranged to form a driving connectionbetween a continuously rotating driving shaft 11 and a normallystationary driven shaft 16 which operates as the driving means for thefilm transport mechanism and which is arranged to be disconnected fromthe continuously rotating shaft 11 and locked in position to preventfurther rotation of the driven shaft 16 after the shutter operation hasbeen completed.

The present invention, as illustrated in the drawings, comprises acontinuously rotating shaft 11 which is driven by an electric motor 13or other suitable means through suitable motion transmitting means suchas gears 12. The shaft 16 is driven by the shaft 11 through suitableconnections including a ratchet wheel 14 having on one face thereofratchet teeth 15 engaged by a suitable pawl 19. Preferably, the ratchetwheel 14 is fixed -to the continuously rotating driving shaft 11 and thepawl 19 is pivotally mounted on a disc member 17 fixed to the shaft 16.The pawl 19 is pivotally attached to the ears of the disc 17 by a pin25.

The pawl 19 is normally urged into engagement with the ratchet teeth 15by a spring urged plunger 26 more clearly shown in Figs. 4 and 5 and, atthe end of an operating cycle, is held away from and out of engage mentwith the ratchet teeth 15 by a pivotable member 21 having a cam slot 22therein. The pivotable member 21 is normally maintained in pawl engagingposition by a biasing spring 24 and is moved out of said position by amovable armature 28 actuated by energizing a solenoid 23.

The solenoid 23 may be energized in any suitable portion of the cyclebut it is preferred that it be energized during the last portion of theshutter operation so that the cam member 21 may be moved out of the filmtransport locking position shown in Fig. 5 to permit the pawl to engagea tooth on the ratchet wheel 14 to cause the shaft 16 to be rotated 360to feed an unexposed portion of film into exposing position.

Fig. 2 shows the pawl member 18 and its carrier, disc member 17, in aposition rotated from Fig. 1. The relative placement of the parts whenthe two shafts 11 and 16 are disengaged from each other, with shaft 11turning alone, is also shown. It will be noted that the pawl member 18is disengaged from the continuously turning toothed disc member 14 and,since the cam plate 21 is in engagement with the projecting portion 20,the

3. QQl 15. and the.. Pawl 1 9. are. Qut 0f contact with each other.

Fig. 3 is a side elevation of the assembly showing the 12a-.wl 169..I inan: engaged position and turnedtao? from the startingpoint.` The;solenoid 25,3, tofwhich the,r caire Z1 is attached, is in a remoteposition from the projecting port-ion 2,0. of the pawl member 1.*8;

Big5 4 is, a topY View of the assemblyl Whichi is-v shown, imFig;A 3,.,Here, the biasing arrangement; canV be; clearly,a seen, fon-urgingandholding; thepawl: 19.A in engagement with the ratchet member 14.Also', there; is depicted the stop 27 which prevents the pawl andiratchet1 sys tem; from jamming:

In Fig. 5 the normal or disengaged position is, shown.; Where'. SQ1I1J-idw 23; S.; inactive: and. the biasingiy spring 24 is, holding the,pivnted.A member 232k. ine the; near. position'.

to, member 118;. and; the projecting: p ortiorn 2th isf. im contact:with:r the Camelot. 22; thepwl: pentium19de-zout;v of contact with thetoothed; driving dise.. L4: andl the sha-ttt 1 6; is. stationary.

Eig.l 6- showsV a topffview.. ofi the mechanism hun does` not'-yincludethe solenoid system: As-shown-thelshafti In? is;v stationary.and.: thepawli and ratchet. are-- out: olA env gagernent with eachother..

Fig. 7. shows an; alternate; springy pressure. arrangement for holdingthe detent: on pawl por-tionl 19: ofi the assembly againstthetootheddisc. member 1.41 of the 'continuously turningi shaft 11; inAsuch a manner thatl saidA shaft 1/1 operates to driye shaft 1:6.whichiin. turn. controlsthe movements within the camera or: other drivendevice.

During a typicalcycle of operation, the following s eries of'mechanicalactions takes. place; The motor 13'? continuously rotates,. drivingthe.A shaft 11V through the gears 12; Tostart the shaft; 16e turning,the solenoid123`- is momentarilyv energized by the operator. at., theproper instant by closing a switch: (not shown)` which sendscurrentflowing through the solenoid windingl Thiscausesthe cam member.2'1";.Which ispivotally secured'l to a-iixedportion ofy the.y assembly,tomove-away from. themember 18thereby causing thecam-surface-ZZ todisengage itself fromme-projecting portion 2020i said memberI 18: Whenthis. occurs, the springassociated with- Thus.; the motor is-now drivingthe shaft 16' through r the" engagedpaWl. and ratchet: arrangement. A*short timeflater-'inzthe cycle the solenoid-23 is ydeenergized andlthebiasing springf24 returns the cam 21'` bach to-its'normal position inthe assembly nearerto'the member'l; Asthe shaft, I6.and the associatedmember 1S- rotate and the cycle nearscompletion, the projecting portion20.of: the member 18- contactsl the-cam-member- 21' and 1eillgages. theinclined# cam surfacefZZ, as illustrated in The'inclinedcam surface 22is shaped insuch a mannerthatf as the projecting portion- 20YX oftheYmember 18 eugagesfwith said camsurface 22, the member 18jiscaused-topivot on itstrunnion relative; tol the member-17: Thisresults in the-dsengagement'of the pawl' portion 19- from thel tooth 15of the disc member 14.' Wlieilthisv occursthe member 18- and thus shaft16: are

brought to a halt and-nolonger-rotate with the driving` shaft 11.

In normaloperation cam-member 21'- will be p ivotedv awayffrom-thememberl 18by thej solenoidjZS only momentarily, which is a suihcient,period of. time to permit the projecting portion 20 to disengage fromthe cam surface 22 and to allow the spring to force pawl 19 intoengagement with the member 14. Shaft 16 will begin rotation at once andwill continue to rotate for one complete revolution. If cam member 21has been returned to the original position, the projecting portion 20 ofthe member 18. will engage. the cam'. surface; at the. completion of onerevolution causing. the pawl 19 to disengage from the tooth 15, aspreviously described;

Although the invention has been described with reference to particularembodiments, it will be understood to those skilled: inthe artthatvariouschanges and modifications can. be made therein. without departingfrom the spirit of the present invention. I intend, therefore, to belimited only by the full scope and spirit of the appended claims.

Hav-ing thusdescribed' myv inventioni what I- claim as newanddesire-to-secure'by Lettere Patent offthe- Unitedl States is:

l'. A clutch mechanism comprising afcontinuouslyrotatingdriving member,afA norrnall,7J stationary drivenA member, a plurality of ratchet teethequally spacedonone face of said drivingl member, apawl memben pi.votally mounted on said driven member and arranged tol be swung intoandiout Ofengagement withisaid ratchet teeth, saidv pawl member being;providedwithany integral cam-engaging portion, a-flatcam'member-havingashapedi cut-out portion for interlocking withi thecamengaging portion ofsaidpawl, saidI camI member being piyotall'ymounted; on a hired portion ofi said clutchmechanism' and arrangedfformovement inaplane extending throughthe axis of? rotation` of-"saidclutchrnechanism intocontact with saidcam engaging portion' f'orswingingkv said pawl'out of#y engagementwith-saidratchet, andfmeans eflfestivey atthe will? ofi the operator toa swing said caml member out offcontact with' the cam'- engaging' portion of said pawl member to permitengagementoffsaidpawlI with said ratchet.

2. A clutchmechanism` comprisingacontinuously roA tatingdriving member,a normallystationary driven` member, a plurality of:V ratchet teethequally'spaced onone face ofA said drivingmernber', a pawl member, earson one face of'said driven member for supporting` said pawl member forswinging movement into` andY out ofi engagement: withsaid ratchet`teeth, biasing means for swinging said pawl into engagement withy saidvratchet; a cam'engaging member'iixedto'saidpawl member, a flatcamfmember having al shapedI cut-out portion for interlocking with said`camu engaging member; said*l cammember being pivotally mounted on afixed portioirof saidclutch mechanism andiarrangedfor movemerrtin aplane extending through Athe axis" ofrotation 'ofsaidclutch mechanismIintol contact with saidengagingmernb'er" forv swinging said pawl out ofengagement'with'-said4 ratchet, and a solenoidA attached 'tosaidcanrrnember bein'g eifec.- tive at-the-will ofthe operator to-move saidcam'member.

out ofl contacirwith` thecam engagingmember' on said* pawlmemberto-perrnit engagement of said-'pawl with said ratchet.-

References-Citediintheiileof this patent UNITED STATES PATENTS 886,004VI othrop Apr: 28, 1908 1,759;630- Rinaldy MayV 2O,` 1930 2,3685892'SkoogY Febl', 19'45v 2,475,740* Goodwin'et` al. Iuly12,`V 1949l2,734,604 Soave Feb; 14,' 1956' 7755129 Peras Dec; 25, .1956

